Secure Capacity Analysis for Magnetic Inductive Coupling-Based SWIPT System

Many researchers have provided meaningful insights for physical layer security (PLS) in various wireless communication systems. However, few works have carried out an intensive PLS analysis for magnetic inductive coupling (MIC)-based simultaneous wireless information and power transfer (SWIPT). This paper analyzes the effect of the angular position of coils on the secure capacity of a MIC-based SWIPT system in the presence of a potential malicious power receiver. Using a simple coupling model, we analyze the maximum achievable secure capacity of a MIC-based SWIPT system when the transmitter has knowledge of the coil angular positions of the receiver and the potential eavesdropper. In addition, we expand our analysis to the case where the transmitter has only limited knowledge of the coil angular positions of the receiver and the potential eavesdropper due to the angular fluctuation of the coils. Since employing the PLS technique with a traditional security algorithm can enhance security, the analysis will provide a meaningful contribution for improving MIC-based SWIPT system security.